1. Field of the Invention
The present invention relates to a socket for electrical parts for detachably accommodating and holding an electrical part such as a semiconductor device (called as xe2x80x9cIC packagexe2x80x9d hereinafter), and more particularly, relates to a socket for electrical parts having elements or parts commonly utilized for different electrical parts.
2. Prior Art of the Invention
In known art, there have been provided IC sockets, as xe2x80x9csocket for electrical partsxe2x80x9d mentioned above, for carrying out performance tests of IC packages as xe2x80x9celectrical partxe2x80x9d.
In such IC socket, a number of contact pins are arranged on a socket body and, in use, the socket body is mounted on a printed circuit board with the IC package being mounted on the socket body. In this state, the contact pins contact terminals of the IC package to thereby establish an electrical connection between the IC socket and the printed circuit board.
In such prior art as mentioned above, however, the IC packages include various types or kinds such as LGA (Land Grid Array), BGA (Ball Grid Array) and PGA (Pin Grid Array), which have different shapes of terminals. Accordingly, it has been required to change the entire of the IC socket when a different type of IC package is used and handled, thus being inconvenient and not economical.
An object of the present invention is to substantially eliminate defects or inconveniences encountered in the prior art mentioned above and to provide a socket for electrical parts having elements or parts commonly utilized for electrical parts, even if kinds or types thereof are different, without exchanging the entire structure of the socket.
This and other objects can be achieved according to the present invention by providing a socket for an electrical part comprising: a socket body; and a contact pin which is provided for the socket body and through which an electrical part having a terminal and a printed circuit board are electrically connected, in which the socket body has a lower plate to be mounted to the printed circuit board and an upper plate which is disposed above the lower plate and on which the electrical part is mounted, wherein the upper plate has a seating portion on which the electrical part is placed in a contacting manner, and the upper plate is exchanged with another one having a seating portion of different height.
According to this aspect, since the upper plates having the seating portions of different heights can be selected and exchanged in accordance with kinds or types of the electrical parts to be used, the lower plate can be commonly utilized while maintaining the contacting pressure between the terminal of the electrical part and the contact pin.
Another preferred aspect of the present inventions is that the contact pin is exchangeable for another one having a different contact shape in accordance with a shape of a terminal of the electrical part.
According to the foregoing aspect of the present invention, the conductive performances between the contact portions of the contact pins and the terminals of the electrical part can be improved.
Another aspect of the present invention is that the contact pin comprises a first plunger electrically connected to the terminal of the electrical part, a second plunger electrically connected to the printed circuit board, a tubular member disposed between the first and second plungers and an elastic member disposed therebetween, the tubular member having one end abutting against one of the first and second plungers and another end slidably contacting other one of the first and second plungers, the elastic member having an urging force for urging the first and second plungers in directions apart from each other, and the first plunger is exchangeable for another one having a different contact shape in accordance with a shape of the terminal of the electrical part.
According to the foregoing aspect of the present invention, the first plungers of the contact pin is exchangeable so that the conductive performance can be also improved with other many parts or elements being common.
Still another aspect of the present invention is that the lower plate is formed with a plurality of lower side through holes into which the second plunger can be inserted, the low side through holes being formed in an arrangement range wider than that of an upper side through holes.
According to the foregoing aspect of the present invention, the socket can be used for an electrical part having different size or shape, or having different number of terminals.
The contact portion may have a mount shape to which a terminal having a land shape contacts. The contact portion may have a V-shaped groove to which a terminal having a solder ball shape or round shape contacts.
According to the foregoing aspect of the present invention, the contact portion of the V-shaped groove makes it possible to avoid damage at the lowest portion of the terminals having round shape. The contact portion may have a plural mount-shape to which a terminal having a pin (rod) shape contacts.
The elastic member is a coil spring disposed inside the tubular member.
The upper plate is provided with the upper plate body, to which the plurality of upper side through holes are formed and on which the electrical part is mounted, and provided with a guide portion for guiding a peripheral edge portion of the electrical part. The guide portion may be formed to be detachable from the upper plate body.
According to the foregoing aspect of the present invention, by exchanging the guide portion for another one, another electrical part having a different size may be utilized.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.